A conceptual rendering shows the Gordie Howe International Bridge crossing the Detroit River from the Delray neighborhood in southwest Detroit.

The consortium of infrastructure companies that will construct the Gordie Howe International Bridge are assuming a fixed cost of more than $2.68 billion to build what will become North America's largest cable-stayed bridge over the Detroit River.

The Canadian government will subsidize $2.12 billion of the cost through monthly "progress payments" during the 74-month construction of the bridge, according to a credit-rating report published Wednesday by S&P Global Ratings.

The Wall Street credit-rating agency assigned a preliminary rating of A- and a stable outlook to $351.5 million in medium and long-term bonds the Bridging North America General Partnership consortium of companies plans to sell to finance its share of the construction costs.

S&P's report said Bridging North America General Partnership will finance construction of the bridge through $806.7 million ($1.04 billion Canadian) in bonds and construction loans and the $2.12 billion ($2.74 billion Canadian) in "progress payments" from the Windsor-Detroit Bridge Authority, a Canadian crown corporation.

The total design and construction cost of $2.68 billion comes out to $3.46 billion in Canadian dollars, with nearly 80 percent being subsidized by the government of Canada.

S&P analysts called the WDBA an "irreplaceable" component to financing the project.

" In our view, the (Canadian) government's commitment under the funding agreement falls short of the requirements of our guarantee criteria," S&P analysts wrote in their credit report. "However, we believe it strengthens the link between WDBA and the (Canadian) government, lifting WDBA's credit profile above what it otherwise would be on a stand-alone basis."

Michigan taxpayers are not contributing a dollar to the infrastructure project under an agreement Gov. Rick Snyder forged with Canadian leaders in 2012.

"The progress payments are payments made by WDBA to the private-sector partner," Mark Butler, spokesman for the Windsor-Detroit Bridge Authority, said in an email to Crain's.

S&P's report was based on data provided by Bridging North America General Partnership and represents the first public disclosure of the potential cost of the long-sought new international crossing linking Michigan and Ontario.

The Windsor-Detroit Bridge Authority has set a deadline of late September for closing on the financing for the project, meaning the figures in the S&P report could still change.

S&P's report said the private construction firms have set a 74-month construction schedule to build and open the bridge by Nov. 30, 2024. That construction schedule includes building the 148-acre U.S. and 131-acre Canadian ports of entry and connections to Interstate 75 in southwest Detroit.

"Importantly, the project has 12 months of cushion in the construction of the cable-stay bridge, which is the most complex component of the project," S&P analysts wrote in their report to potential investors.

In July, the Windsor-Detroit Bridge Authority selected the Bridging North America General Partnership consortium to design, finance, build and operate the Gordie Howe bridge for 36 years.

According to S&P, the ownership in the Bridging North America General Partnership is split as follows: ACS Infrastructure Canada Inc. (40 percent), Fluor Canada Ltd. (40 percent) and Aecon Concessions (20 percent; a division of Aecon Construction Group Inc.).

"Toll revenues flow to the WDBA, and the project is not exposed to toll revenue risk and has no role in setting toll rates," according to the S&P report.

The Bridging North America General Partnership, or BNA, plans to sell $351.5 million ($454.5 million Canadian) in medium and long-term bonds and take out a $454 million construction loan ($587 million Canadian).

About 45 percent of the construction spending will occur between May 2021 and May 2023, according to the Bridging North America General Partnership.

S&P said its stable credit outlook was based, in part, on the track record of the large infrastructure companies involved in the project.

"The outlook is stable, with the expectation that the project will complete construction on time and within budget, given the very experienced construction contractor and the clear assignment of risk within the concession, along with adequate liquidity to sustain delays under our downside scenario," S&P said in its report.

Once complete, the six-lane main span of the Gordie Howe bridge will measure more than a half-mile long and be the longest cable-stayed bridge in North America.

Upon completion of the bridge project, the state of Michigan will be responsible for the maintenance and upkeep of the new ramps connecting I-75 to the customs plaza in Delray, according to the S&P report.